Preparation Of Edible Coating Solution And Its Preservation Effects On Refrigerated Marinated Eggs

This research was one of the research contents of the Science and Technology Development Program of Jilin Provincial Department of Science and Technology(Key Technology and Application for Improving the Quality of Long-Shelf-Life Leisure Egg Products,20210202056NC).Marinated Egg is one of the traditional egg products in China with a long history,rich nutrition and unique taste,which was popular both domestically and abroad.Fresh marinated eggs that are not sterilized by high temperature packaging can maximize the retention of the nutrition,taste,and flavor.However,due to the effects of microorganisms and their enzyme,marinated eggs are prone to spoilage and shelf-life reduction,which seriously restricts their sales and even endangers consumers’ health.Therefore,developing preservation techniques for fresh marinated eggs is of great significance for delaying spoilage,maintaining their unique flavor and nutritional quality.Among many preservation techniques,coating preservation has gradually entered researchers’ vision due to its unique preservation mode and ability to release loaded active substances.Chitosan,as the most common coating preservation material,is currently limited to the study of the preservation effect of meat products,seafood,fruits,and vegetables,and has not been extensively studied for marinated eggs.In this paper,marinated eggs were selected as the research object,and chitosan was used as the coating material,ε-polylysine hydrochloride(ε-PLH)and nisin were used as antibacterial agents,and tea polyphenols(TP)and ascorbic acid(also known as vitamin C(VC))were used as antioxidants to prepare edible coating solutions.The physicochemical properties of the coating solution were determined by antibacterial properties,antioxidant activity,rheological properties,DSC,infrared spectroscopy,particle size,potential,color difference,and other physical and chemical indicators;the preservation effect of refrigerated marinated eggs was evaluated by microbial,physicochemical properties,sensory evaluation,and other physical and chemical indicators.The effect of the coating solution on inhibiting the oxidation of marinated egg protein was explored by total sulfhydryl,surface hydrophobicity,and casein content,among other indicators.(1)According to the indices of antibacterial activity,antioxidant activity,physical properties(particle size,potential,PDI,p H,turbidity,color difference),rheological properties,infrared spectroscopy,and DSC analysis,the edible coating solution added with ε-PLH,Nisin,TP,and VC was comprehensively evaluated.The results showed that ε-PLH,Nisin,TP,and VC significantly enhanced the antibacterial and antioxidant properties of the edible coating solution.Meanwhile,due to the interactions among the components,the rheological properties and thermal stability of the edible coating solution were significantly improved,and the particle size,potential,and other indicators of the coating solution were significantly improved as well.(2)Using physical properties(water-holding capacity,water content,color difference,texture,appearance changes),sensory characteristics,microbiological properties(Total Viable Counts),and chemical properties(p H value)as indicators,the preservation effect of chitosan,ε-PLH,Nisin,TP,and VC(CS-NH-TC)composite edible coating on refrigerated marinated eggs was evaluated,with the control groups being a blank group(CK),chitosan alone coating(CS),chitosan,ε-PLH,and Nisin coating(CS-Nisin-ε-PLH group),and chitosan,TP,and VC coating(CS-TP-VC).The results showed that the CS-NH-TC edible coating treatment significantly delayed the deterioration of sensory quality,water content,water-holding capacity,and other indicators,as well as the increase in total viable counts during refrigeration of marinated eggs.Compared with other groups,the shelf life of marinated eggs in the CS-NH-TC group could be extended to 20 days.(3)Refrigerated marinated eggs were treated with CS-NH-TC edible coating,and the effect of CS-NH-TC edible coating on the protein oxidation of marinated eggs was analyzed by indicators such as total sulfhydryl content,hydrophobicity,protein solubility,casein content,intermolecular forces,and particle size changes.The results showed that CS-NH-TC edible coating treatment delayed the protein oxidation and denaturation of marinated eggs and stabilized the spatial structure of the protein to some extent.The antioxidants in the edible coating solution delayed the increase in surface hydrophobicity,casein content,particle size,turbidity,and other indicators of marinated egg protein,and the decrease in total sulfhydryl and protein solubility was slow.